1. Field of the Invention
The invention relates in general to a printed wide band monopole antenna module, and more particularly to an antenna module, which is directly printed on one side of the printed circuit board and used in a portable electronic device and is capable of performing wireless signal transmission and easily adjusting the operating frequency band and bandwidth according to the needs in actual applications.
2. Description of the Related Art
Along with the development in the mobile computation technology, various portable electronic devices such as notebook computer, personal digital assistant, mobile phone and tablet PC are invented and provided. These portable electronic devices have become indispensable to people and brought about tremendous convenience and practicality in their everyday life. Wireless signal transmission such as telephone communication and Internet connection is an important application of the portable electronic devices. Here, wireless signal transmission refers to the reception and transmission of related wireless signals through a built-in and an external antenna by way of radio frequency (RF).
As the portable electronic devices have the features of lightweight, slimness and compactness, related wireless signal transmission modules are also designed and manufactured according to the same features. In terms of the technologies currently available, there are two types of small-sized antennas: chip antenna and planar antenna. The chip antenna includes ceramic chip antenna, while the planar antenna includes micro-strip antenna and printed antenna. Of the planar antennas, the planar inverse-F antenna (PIFA) and the monopole antenna, having the advantages of light structure, excellent transmission efficiency, and simple manufacturing process, can be easily disposed on the inner wall of the device and have been widely used in various portable electronic devices.
To enhance the function and practicality of wireless signal transmission of the portable electronic device, the design of wireless signal transmission module is directed towards multi-band and sufficient bandwidth. For example, to integrate the wireless LAN standards 802.11b and 802.11a in one wireless signal transmission module, the antenna structure or circuit must be capable of operating under two frequencies 2.4 GHz and 5 GHz. The antenna having two operating frequencies is referred as dual-band antenna.
According to the current manufacturing technologies of the planar inverse-F antenna (PIFA), the inner/outer conductive layer of the co-axial cable are respectively soldered on a signal feeding point and a signal ground point of the structure for transmitting the signals. However, to equip the planar inverse-F antenna with the multi-band and the wide band function, the design of the antenna becomes more complicated and the size is increased in most generally known technologies. The complicated and large-sized design will incur higher manufacturing cost and involve more assembly difficulties, and the bandwidth becomes narrower and the frequency band is difficult to adjust under different environments. In contrast, the operation and structure of the monopole antenna are simpler than the PIFA. Therefore, it is a prominent object of the disclosure to provide a monopole antenna, which uses the same antenna or the same wireless signal transmission module and is capable of effectively performing the multi-band and the wide band function.